The design and construction of wind instrument keys has remained relatively static over a number of years. Manufacturers have been reluctant to alter an accepted design for fear of a lack of acceptance by the musicians in that radically new key systems require some relearning by the musician. Prior art keys, while suited for their intended purpose, are not designed or constructed with durability, ease of repair or ease of playing in mind. While the keys may be acceptable when new, continued use results in bending and fatigue in much of the key structure. Continuous adjustment is thus required resulting in added expense to the musician and rendering the instrument unusable during the repair process.
Prior art keys have one relatively narrow arm portion connecting the tone hole cover with the hinge. When pressure is applied at the finger contact point of the cover a twisting of the arm can occur resulting in air leaks due to improper sealing between the tone hole cover and the tone hole. Pressure at the contact point may also cause the arm to bend causing misalignment of the tone hole cover with the tone hole. This problem may be especially acute in a long key. In addition, handling or storage of the instrument may put pressure on the arm also causing misalignment of the tone hole cover with the tone hole.
Another limitation of prior art keys is their propensity to spread between the arm and foot portions. The arm and foot portions are connected adjacent the hinge and, when the key is released, the shock of the stop on the foot contacting the side of the tone hole may cause spreading between the arm and foot portions of the key. In combination type keys, where one key activates one or more other keys, spreading is a critical problem because one key may contact its tone hole sooner or later than the other key or keys depending upon the amount of spreadng between the arm and foot portions. The result is that some of the keys do not close off the tone hole completely thereby allowing air leaks between the tone hole and the tone hole cover.
A problem similar to that discussed above relates to combination keys in which a foundation extends from one tone hole cover to another. The sudden force of closure may twist the arm and bend the foundation. When this occurs, the tone hole covers will not completely close and air leaks may result.
Besides the problem of arm twisting and bending of the arm portion of keys, the foot portions are also subject to the same problem. That is, the foot portions can move from side to side resulting in problems when other keys are activated by the foot portion. Bending of the foot portions also may result in the foot not contacting the stop as required. This may mean the critical distance between the tone hole cover and its tone hole when open may vary with time requiring considerable flexibility and adaptability by the instrument player in order to control pitch.
The bending of posts which support the hinges may also cause misalignment of the tone hole covers with the tone holes resulting in air leaks. Bent posts may bend or stress hinges thereby causing keys on the hinge to bind in addition to misalignment. Presently used posts are a single rod or shaft attached to the instrument body on one end and supporting the hinge on the opposite end.
Prior art keys have pads which are subject to air leaks caused by uneven pad tension due to shrinking or movement of the pad from moisture or other factors. The pad includes a skin which may shrink if exposed to moisture such as saliva which is carried through the tone hole. Prior art pads employ a skin material on a cushion which fits on the underside of the tone hole cover. The skin material extends around the sides of the cushion layer and is fastened to the top of the cushion. Excess tension on the skin due to moisture induced shrinking or other factors, causes it to compress the cushion layer near the edge of the tone hole cover thereby rendering the pad uneven. Air may then leak between the pad and the tone hole.
Another limitation of prior art wind keys relates to the difficulty in replacing springs when they have been worn or are otherwise in need of repair. It is necessary to remove the entire key to replace conventional springs. Repairs are thus more complicated and expensive then would be the case if the spring could be easily removed. Similarly, adjustments to the spring are difficult and require key removal.
There is a large amount of key vibration due to the playing of the instrument. Thus, many of the set screws used as stops or for other purposes in prior art keys tend to vibrate loose. Continual adjustment of these screws is thus required to keep the keys in proper playing condition.
Problems with unwanted noise due to the metal on metal contact between moving key parts plague all wind instrument musicians. This noise is distracting and may disrupt the concentration of the musician as well as contribute to undesirable background noise. One of the largest contributors to this unwanted noise is the movement of the hinge rod in the post hole. In prior devices, there is a small amount of clearance between the hinge rod and the post hole allowing the hinge rod to click back and forth with the sudden stopping of a key.
For acoustical reasons tone holes must vary in size such that there is some unevenness in tone and sound radiation. In prior art keys the structure which supports the tone hole cover is not designed to affect sound radiation.
Problems with movement of a musician's finger from one finger button to another in a cluster of keys result in more difficult playing of the instrument. These finger buttons are generally located side by side such that when one button is depressed the transition to another button requires a sliding movement of the finger. This motion is especially awkward because of interruption in the movement of the finger as it contacts the edge of the second button. Some attempts have been made to alleviate this problem by attaching the buttons to one another thereby causing the second button to tilt when the first button is depressed. While this aids finger movement somewhat, considerable awkwardness remains. That is, the finger must overcome general frictional resistance as well as the sudden resistance accompanying finger movement from the plane of one button to the second tilted button. There is also no definite guide for the fingers to move from one button to another.